stdbool.in.h

/* Copyright (C) 2001-2003, 2006-2010 Free Software Foundation, Inc. Written by Bruno Haible <haible@clisp.cons.org>, 2001. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */#ifndef _GL_STDBOOL_H#define _GL_STDBOOL_H/* ISO C 99 <stdbool.h> for platforms that lack it. *//* Usage suggestions: Programs that use <stdbool.h> should be aware of some limitations and standards compliance issues. Standards compliance: - <stdbool.h> must be #included before 'bool', 'false', 'true' can be used. - You cannot assume that sizeof (bool) == 1. - Programs should not undefine the macros bool, true, and false, as C99 lists that as an "obsolescent feature". Limitations of this substitute, when used in a C89 environment: - <stdbool.h> must be #included before the '_Bool' type can be used. - You cannot assume that _Bool is a typedef; it might be a macro. - Bit-fields of type 'bool' are not supported. Portable code should use 'unsigned int foo : 1;' rather than 'bool foo : 1;'. - In C99, casts and automatic conversions to '_Bool' or 'bool' are performed in such a way that every nonzero value gets converted to 'true', and zero gets converted to 'false'. This doesn't work with this substitute. With this substitute, only the values 0 and 1 give the expected result when converted to _Bool' or 'bool'. - C99 allows the use of (_Bool)0.0 in constant expressions, but this substitute cannot always provide this property. Also, it is suggested that programs use 'bool' rather than '_Bool'; this isn't required, but 'bool' is more common. *//* 7.16. Boolean type and values *//* BeOS <sys/socket.h> already #defines false 0, true 1. We use the same definitions below, but temporarily we have to #undef them. */#if defined __BEOS__ && !defined __HAIKU__# include <OS.h>/* defines bool but not _Bool */# undef false# undef true#endif/* For the sake of symbolic names in gdb, we define true and false as enum constants, not only as macros. It is tempting to write typedef enum { false = 0, true = 1 } _Bool; so that gdb prints values of type 'bool' symbolically. But if we do this, values of type '_Bool' may promote to 'int' or 'unsigned int' (see ISO C 99 6.7.2.2.(4)); however, '_Bool' must promote to 'int' (see ISO C 99 6.3.1.1.(2)). So we add a negative value to the enum; this ensures that '_Bool' promotes to 'int'. */#if defined __cplusplus || (defined __BEOS__ && !defined __HAIKU__)/* A compiler known to have 'bool'. *//* If the compiler already has both 'bool' and '_Bool', we can assume they are the same types. */# if !@HAVE__BOOL@typedefbool _Bool;
# endif#else# if !defined __GNUC__/* If @HAVE__BOOL@: Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when the built-in _Bool type is used. See http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html Similar bugs are likely with other compilers as well; this file wouldn't be used if <stdbool.h> was working. So we override the _Bool type. If !@HAVE__BOOL@: Need to define _Bool ourselves. As 'signed char' or as an enum type? Use of a typedef, with SunPRO C, leads to a stupid "warning: _Bool is a keyword in ISO C99". Use of an enum type, with IRIX cc, leads to a stupid "warning(1185): enumerated type mixed with another type". Even the existence of an enum type, without a typedef, "Invalid enumerator. (badenum)" with HP-UX cc on Tru64. The only benefit of the enum, debuggability, is not important with these compilers. So use 'signed char' and no enum. */# define _Bool signed char# else/* With this compiler, trust the _Bool type if the compiler has it. */# if !@HAVE__BOOL@typedefenum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
# endif# endif#endif#define bool _Bool/* The other macros must be usable in preprocessor directives. */#define false 0#define true 1#define __bool_true_false_are_defined 1#endif /* _GL_STDBOOL_H */